1. Field of the Invention
The present invention relates to hydraulic tools and, more particularly, to a compact portable hydraulic tool.
2. Brief Description of Earlier Developments
Hydraulic power tools are used in numerous applications to provide users with a desired mechanical advantage. One such application is in crimping tools used for making crimping connections such as for example crimping power connectors onto conductors. In this case, it is desired that the hydraulic crimping tools be portable in order to bring the tool to the job site. Conventional hydraulic crimping tools are generally heavy and thus cumbersome to handle during operation. The reason for this is that the crimping tools may be subjected to high loads during operation and are provided with structure capable of withstanding such loads. For instance, the movable adapter of a hydraulic crimping tool may often be subjected to considerable non-axial loads (i.e. loads which are not aligned with the axis of travel of the movable adapter in the tool). The non-axial loads on the movable adapter can cause the tool to bind or may even cause failure of the tool during operation. The approach taken to prevent misalignment and binding of the movable adapter under non-axial loads in conventional tools has been to provide the movable adapter and support frame with keying mechanism. However, this results in an increase in the size of both the adapter and support frame of the tool and a corresponding increase in weight. One example of a conventional hydraulic compression tool is shown in U.S. Pat. No. 5,934,136. This tool has a compression head with movable dies each having two guide plates slidably engaging with guide grooves formed into the frame of the compression head.
Another feature desired on hydraulic compression tools is the ability to rapidly advance the movable adapter when closing up gaps between the work piece, such as a crimping connector, and the movable adapter. This allows the user to perform the crimping operation faster, and using a smaller number of pump strokes which is important especially in the case of a manually operated hydraulic crimping tool.
U.S. Pat. Nos. 4,942,757 and 4,947,672, which are hereby incorporated by reference, disclose hydraulic tools with movable rams. FCI USA Inc. sells a hand operated hydraulic tool, type Y750 which has a rapid advance two stage pump and a type Y35 with a rotatable handle for rapid ram advance.
U.S. Pat. No. 5,979,215, which is also incorporated by reference herein in its entirety, discloses a hydraulic tool with an arm and a mechanical actuator in the hydraulic conduit system for contacting a rear end of the ram. Conventional hydraulic crimping tools which have a ram with a rapid advance feature may employ a multi-stage pump or a multi-stage ram piston in order to provide the rapid advance feature. The hydraulic fluid conduit system to route fluid from the multiple stages of the multi-stage pump to the hydraulic fluid contact surface of the ram is complex with numerous parallel conduits between the pump and ram. Accordingly, an extensive amount of machining or fabrication may be involved in forming such a conduit system in the hydraulic tool. The complexity of the hydraulic conduit system has commensurate impact on the time and cost of manufacturing the tool. In the case of a multi-stage ramp piston, the size and length of the ram is increased to accommodate the multiple stages. The longer, larger ram uses a correspondingly longer, larger hydraulic cylinder which in turn increases the size and hence the weight, as well as the cost of the tool. The instant invention overcomes the problems of conventional hydraulic crimping tools as will be described in greater detail below.
In accordance with the first embodiment of the present invention a hydraulic tool is provided. The hydraulic tool comprises a frame, and a movable adapter. The frame has a work space with an anvil adapter at one end and a substantially flat face guide surface on one side of the workspace. The movable adapter is used for working a piece in the workspace against the anvil adapter. The movable adapter is movably mounted to the frame to move in the workspace relative to the frame along an axis of translation. The movable adapter has a substantially flat face seating surface seated against the guide surface of the frame. When the movable adapter is moved, the seating surface of the movable adapter rides upon the guide surface. The seating surface and guide surface interface with each other in order to maintain the movable adapter in a predetermined orientation relative to the frame.
In accordance with a second embodiment of the present invention, a hydraulic tool is provided. The hydraulic tool comprises a frame, and a movable adapter. The frame has an anvil adapter and a substantially flat guide surface. The movable adapter is movably mounted to the frame to move relative to the frame along an axis of translation. The movable adapter is adapted for working a workpiece in cooperation with the anvil adapter and has a substantially flat support surface seated against the guide surface. The support surface and guide surface interface to prevent rotation of the movable adapter about the axis of translation. The frame includes a bearing surface adapted for maintaining the alignment of the movable adapter with the axis of translation. The bearing surface is disposed in the frame so that the movable adapter does not contact the bearing surface.
In accordance with a third embodiment of the present invention, a hydraulic tool is provided. The hydraulic tool comprises a frame, a ram assembly, and a hydraulic fluid conduit system. The frame has a hydraulic fluid reservoir connected to the frame. The ram assembly is movably mounted to the frame. The ram assembly comprises an outer ram, and an inner ram housed in the outer ram. Both inner and outer rams are movable relative to the frame. The hydraulic fluid conduit system is disposed in the frame between the ram assembly and the fluid reservoir. The outer ram is adapted to be advanced relative to the frame by the inner ram and by hydraulic fluid pressure against the outer ram. The outer ram is advanced by the inner ram pressing against the outer ram when hydraulic fluid pressure in the conduit system is below a predetermined pressure. The outer ram is advanced by hydraulic fluid against the outer ram when hydraulic fluid pressure in the conduit system is above the predetermined pressure.
In accordance with a fourth embodiment of the present invention, a hydraulic tool is provided. The hydraulic tool comprises a frame, a hydraulic fluid conduit system, a ram, and a rapid advance ram actuator. The frame has a hydraulic fluid reservoir connected to the frame. The hydraulic fluid conduit system extends through the frame from the reservoir. The ram is movably mounted to the frame. The ram is adapted to be moved relative to the frame by hydraulic fluid from the conduit system. The rapid advanced ram actuator is movably mounted to the frame for advancing the ram through at least part of the ram travel. The rapid advance ram actuator has one end contacting the ram and another end with an actuator hydraulic fluid contact surface for moving the rapid advance ram actuator relative to the frame using hydraulic fluid from the conduit system. The ram has a chamber formed therein. The rapid advance ram actuator is located inside the chamber in the ram.